Why non-extended silicone is the standard for exterior steel applications.
In exterior construction, sealant choice isn’t a matter of preference, it’s a matter of performance, durability, and risk management.
As Australia’s use of coated steel continues to grow across roofing, wall cladding, flashing and rainwater systems, industry bodies and manufacturers are now clearer than ever on what works best outdoors: 100% neutralcure silicone sealants.
Recent technical guidance from both the Australian Steel Institute (ASI) and BlueScope, Australia’s leading coated steel manufacturer, reinforces a simple message to the construction supply chain — not all silicones are created equal, and extended formulations introduce unnecessary risk in exterior applications.
Industry Direction Is Clear: The Australian Steel Institute’s Technical Specification TS001, released to guide silicone sealant selection for external steel cladding systems, outlines minimum performance requirements for applications including roofing, flashing, wall cladding and rainwater goods, where long-term weatherproofing is critical to performance.
Similarly, BlueScope’s Technical Bulletin TB09 specifies that sealants used on exterior BlueScope coated steel must be:
- Neutral-curing silicone
- Capable of strong adhesion to finished steel surfaces
- Flexible across extreme temperature ranges
- Resistant to UV degradation
- Suitable for use without primer in most applications
Together, these endorsements point to one outcome: non-extended, high silicone-content sealants provide the most reliable long-term performance on coated steel.
The Hidden Cost of Extended Silicone: Extended silicone sealants can look similar at point of sale — but performance over time tells a very different story. By incorporating fillers and extenders, these products often sacrifice flexibility, adhesion and UV stability.
In real-world exterior conditions, this can result in:
- Shrinkage and cracking
- Yellowing and loss of appearance
- Inconsistent adhesion to coated steel
- Premature joint failure — sometimes within months
No Fillers. No Compromise. No Risk.: Admil’s ProSil Silicone range which includes ProSil N192 & 10 is a 100% neutralcure silicone — no fillers, no extenders, and no performance shortcuts. Designed specifically for exterior applications, it aligns with ASI TS001 requirements and meets BlueScope’s TB09 recommendations for coated steel. Testing across Colorbond®, Zincalume®, Trimdeck® and galvanised steel, including accelerated ageing and elevated temperature trials, has demonstrated consistent adhesion and long-term stability — particularly where extended silicone alternatives showed variability.
ProSil N192 & ProSil 10 also delivers confidence through:
- AS/NZS 4020 potable water approval
- BRANZ appraisal
- WaterMark certification
- Low-VOC compliance
- Proven UV and temperature resistance
A Smarter Choice for Distributors: Stocking 100% silicone isn’t just about meeting today’s specifications — it’s about protecting your customers, your reputation, and your margin long term.
With Admil ProSil N192 & ProSil 10, distributors can confidently offer a sealant that reflects current industry guidance, meets manufacturer expectations, and reduces downstream risk.
